This invention generally relates to multi-chamber syringes for use in delivering drugs to medical patients. In particular, this invention relates to dual-chamber syringes that allow solid medicine (such as lyophilized material or powder) and liquid solvent (such as water or saline) to be pre-mixed prior to injection into a patient.
Conventionally powdered medicine, liquid solvents and injection device are normally used when powdered injection medicines are given. The powdered medicines are filled aseptically into a vial or an ampule container (referred to as a “carpule” hereinafter). As liquid solvents, distilled water for injection or an isotonic sodium chloride solution are filled aseptically in an ampule or carpule. Typically a syringe is used as the injection device.
It is known in the prior art to provide a syringe having two chambers: one filled with the solid medicine and the other filled with liquid solvent. The solid and liquid are pre-mixed before injection into a human body.
There is a need for an improved system to enable the delivery of drugs that come in two forms (i.e. lyophilized matter or powder and liquid solvent) that need to be premixed in an easy, single use, such as when injecting botulinum toxin. Preferably the improved system is sterilizable, uses disposable carpules, and allows blood to be aspirated to alert the operator that he/she is mistakenly in a blood vessel.